OLED lighting based on white broadband copolymer emitters

Abstract

OLEDs for lighting applications are gaining increasing attention due to the possibility to produce large area, 2-dimensional light sources. In contrast to the existing technology e.g. based on white inorganic LEDs this offers a completely new freedom in design for applications of next generation lighting. Today, different approaches to achieve white broadband emission for organic lighting solutions are investigated ranging from devices with blue emission in combination with conversion layers to RGB-color by lateral patterning with the support of active color tunability. Within this contribution we present results of broadband emitting copolymers to achieve white emission. New requirements arising from the shift of OLEDs in a display configuration to those for lighting applications are discussed with focus on the electro-optical behavior. Furthermore, we describe challenges that result from using large active areas and investigate ways to improve large area lighting tiles

Efficiency analysis of organic light-emitting diodes based on optical simulation

“…Diffuse layers (i.e. scattering particles in a transparent matrix [1][2][3][4]), microstructured films (e.g. microlens arrays [5]) or roughened substrates [6] are well-known techniques for this purpose.…”

OLED lighting: light where it never has been before

“…Here, we define η s-a as the fraction of photons that is coupled into the substrate that is extracted into the ambient. Light extraction enhancement due to volumetric light scattering by particles in diffusive layers has already been investigated by Gärditz et al 14 and Shiang et al 15 . However, major differences between down-conversion layers and diffusive layers regarding the physical processes within the layers and the purpose of the substrate surface modifications exist.…”

Overcoming Challenges in OLED Technology for Lighting Solutions

“…A solution to phase separation is to combine the various components of the blend, as occurs with copolymerization into a single copolymer of different chromophores covering the entire visible spectrum [83][84][85]. Polymeric OLEDs also provide the advantage of being easily manufacturable but require careful molecular design to ensure the uniform distribution of the chromophores within the film and to control the energy transfer between species.…”